Add utility to prepare files in a similar way to directories
Bug: 28785119
Bug: 28625993
Change-Id: I505eb4deca0a89f64fe4505dd6729fe6a48bc1aa
diff --git a/libcutils/fs.c b/libcutils/fs.c
index 5e2ef0b..3f14de7 100644
--- a/libcutils/fs.c
+++ b/libcutils/fs.c
@@ -37,10 +37,11 @@
#define ALL_PERMS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
#define BUF_SIZE 64
-static int fs_prepare_dir_impl(const char* path, mode_t mode, uid_t uid, gid_t gid,
- int allow_fixup) {
+static int fs_prepare_path_impl(const char* path, mode_t mode, uid_t uid, gid_t gid,
+ int allow_fixup, int prepare_as_dir) {
// Check if path needs to be created
struct stat sb;
+ int create_result = -1;
if (TEMP_FAILURE_RETRY(lstat(path, &sb)) == -1) {
if (errno == ENOENT) {
goto create;
@@ -51,10 +52,12 @@
}
// Exists, verify status
- if (!S_ISDIR(sb.st_mode)) {
- ALOGE("Not a directory: %s", path);
+ int type_ok = prepare_as_dir ? S_ISDIR(sb.st_mode) : S_ISREG(sb.st_mode);
+ if (!type_ok) {
+ ALOGE("Not a %s: %s", (prepare_as_dir ? "directory" : "regular file"), path);
return -1;
}
+
int owner_match = ((sb.st_uid == uid) && (sb.st_gid == gid));
int mode_match = ((sb.st_mode & ALL_PERMS) == mode);
if (owner_match && mode_match) {
@@ -74,13 +77,21 @@
}
create:
- if (TEMP_FAILURE_RETRY(mkdir(path, mode)) == -1) {
+ create_result = prepare_as_dir
+ ? TEMP_FAILURE_RETRY(mkdir(path, mode))
+ : TEMP_FAILURE_RETRY(open(path, O_CREAT | O_CLOEXEC | O_NOFOLLOW | O_RDONLY));
+ if (create_result == -1) {
if (errno != EEXIST) {
- ALOGE("Failed to mkdir(%s): %s", path, strerror(errno));
+ ALOGE("Failed to %s(%s): %s",
+ (prepare_as_dir ? "mkdir" : "open"), path, strerror(errno));
return -1;
}
+ } else if (!prepare_as_dir) {
+ // For regular files we need to make sure we close the descriptor
+ if (close(create_result) == -1) {
+ ALOGW("Failed to close file after create %s: %s", path, strerror(errno));
+ }
}
-
fixup:
if (TEMP_FAILURE_RETRY(chmod(path, mode)) == -1) {
ALOGE("Failed to chmod(%s, %d): %s", path, mode, strerror(errno));
@@ -95,11 +106,15 @@
}
int fs_prepare_dir(const char* path, mode_t mode, uid_t uid, gid_t gid) {
- return fs_prepare_dir_impl(path, mode, uid, gid, 1);
+ return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 1, /*prepare_as_dir*/ 1);
}
int fs_prepare_dir_strict(const char* path, mode_t mode, uid_t uid, gid_t gid) {
- return fs_prepare_dir_impl(path, mode, uid, gid, 0);
+ return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 0, /*prepare_as_dir*/ 1);
+}
+
+int fs_prepare_file_strict(const char* path, mode_t mode, uid_t uid, gid_t gid) {
+ return fs_prepare_path_impl(path, mode, uid, gid, /*allow_fixup*/ 0, /*prepare_as_dir*/ 0);
}
int fs_read_atomic_int(const char* path, int* out_value) {